Cutting wire assembly for use with a catheter

1. A method of treating a lesion in a body lumen in a patient's body, the method comprising:

inserting a tracking member and a plurality of cutting members through a first lumen of a catheter;

withdrawing the catheter from the cutting members and tracking member and removing the catheter from the body lumen;

subsequently inserting the catheter over a proximal end of the tracking member extending outside the patient's body, and leaving the cutting members outside the catheter as the catheter is advanced over the tracking member; and

expanding a portion of the catheter to move the cutting members into cutting contact with the lesion to thereby enlarge a passageway in the body lumen.

2. The method of claim 1 , wherein the portion of the catheter to move the cutting members includes an expandable balloon, and the step of expanding a portion of the catheter includes a step of expanding the balloon.

3. The method of claim 2 , wherein the step of expanding the balloon causes the plurality of cutting members to be moved radially with respect to the catheter.

4. The method of claim 1 , wherein the step of expanding a portion of the catheter causes a gap between the cutting members and tracking guidewire to widen.

5. The method of claim 1 , wherein the cutting members have a cutting surface on a first surface opposite a second surface facing the tracking member, and expansion of the portion of the catheter forces the cutting surfaces into contact with the lesion.

6. The method of claim 1 , wherein at least one of the cutting members and the tracking member are attached at a distal end and inserted as a unit through the first lumen of the catheter.

7. The method of claim 1 , wherein a length of the tracking member exceeds a length of the cutting members.

8. The method of claim 1 , wherein the cutting members have a first portion of a first configuration and a second portion of a second configuration, the second portion including a cutting surface and the first portion being atraumatic.

9. The method of claim 8 , wherein a height of the second portion is less than a height of the first portion.

10. The method of claim 1 , further comprising marker bands on the tracking member.

11. The method of claim 1 , wherein the tracking member has a coil at a distal tip.

12. The method of claim 11 , further comprising a shrink wrap over a portion of the tracking member and a portion of the cutting members.

13. A method of treating a lesion in a body lumen in a patient's body, the method comprising:

inserting a plurality of cutting members and a tracking member into a vessel;

subsequently inserting a catheter into the patient's body over a proximal end of the tracking member extending outside the patient's body so the tracking member extends through a first lumen of the catheter and the cutting members do not extend through the first lumen; and

moving the cutting members away from the tracking member into cutting contact with the lesion to enlarge a passageway in the body lumen.

14. The method of claim 13 , wherein the step of inserting the plurality of cutting members and tracking member comprises a step of inserting the cutting members and tracking member through a lumen of the same catheter subsequently inserted over the tracking member.

15. The method of claim 13 , wherein the step of moving the cutting members comprises a step of expanding a balloon of the catheter.

16. The method of claim 13 , wherein the cutting members and tracking member are attached at a distal end and inserted as a unit into the vessel.

17. The method of claim 13 , wherein the cutting members are wires and the tracking member is a wire.

18. The method of claim 17 , wherein the cutting members are substantially circular in cross-section in a proximal region and substantially triangular in a distal region.

19. A method of treating a lesion in a body lumen, the method comprising:

inserting a plurality of cutting members and a tracking member into the vessel;

inserting a catheter over the tracking member so the tracking member extends through a first lumen of the catheter and the cutting members do not extend through the first lumen; and

moving the cutting members away from the tracking member into cutting contact with the lesion to enlarge a passageway in the body lumen;

wherein the step of inserting the plurality of cutting members and tracking member includes a step of inserting the cutting members and tracking member through a lumen of a second catheter, the second catheter being different than the catheter inserted over the tracking member.